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The Laurentide Ice Sheet was a massive sheet of ice that covered millions of square miles, including most of
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...
and a large portion of the
Northern United States The Northern United States, commonly referred to as the American North, the Northern States, or simply the North, is a geographical or historical region of the United States. History Early history Before the 19th century westward expansion, the "N ...
, multiple times during the
Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million year ...
glacial A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...
epochs, from 2.58 million years ago to the present. The last advance covered most of northern North America between c. 95,000 and c. 20,000 years before the present day and, among other geomorphological effects, gouged out the five
Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
and the hosts of smaller lakes of the
Canadian Shield The Canadian Shield (french: Bouclier canadien ), also called the Laurentian Plateau, is a geologic shield, a large area of exposed Precambrian igneous and high-grade metamorphic rocks. It forms the North American Craton (or Laurentia), the anc ...
. These lakes extend from the eastern
Northwest Territories The Northwest Territories (abbreviated ''NT'' or ''NWT''; french: Territoires du Nord-Ouest, formerly ''North-Western Territory'' and ''North-West Territories'' and namely shortened as ''Northwest Territory'') is a federal territory of Canada. ...
, through most of northern Canada, and the upper
Midwestern United States The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of the United States. I ...
(
Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over t ...
,
Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...
, and
Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and t ...
) to the
Finger Lakes The Finger Lakes are a group of eleven long, narrow, roughly north–south lakes located south of Lake Ontario in an area called the ''Finger Lakes region'' in New York, in the United States. This region straddles the northern and transitional ...
, through
Lake Champlain , native_name_lang = , image = Champlainmap.svg , caption = Lake Champlain-River Richelieu watershed , image_bathymetry = , caption_bathymetry = , location = New York/ Vermont in the United States; and Quebec in Canada , coords = , type ...
and Lake George areas of
New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...
, across the northern
Appalachians The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They ...
into and through all of
New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...
and
Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native Eng ...
. At times, the ice sheet's southern margin included the present-day sites of coastal towns of the
Northeastern United States The Northeastern United States, also referred to as the Northeast, the East Coast, or the American Northeast, is a geographic region of the United States. It is located on the Atlantic coast of North America, with Canada to its north, the Southe ...
, and cities such as
Boston Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- mo ...
and
New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...
and Great Lakes coastal cities and towns as far south as
Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = List of sovereign states, Count ...
and St. Louis, Missouri, and then followed the present course of the Missouri River up to the northern slopes of the Cypress Hills, beyond which it merged with the Cordilleran Ice Sheet. The ice coverage extended approximately as far south as 38 degrees latitude mid-continent.


Description

This ice sheet was the primary feature of the
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
epoch in North America, commonly referred to as the
ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gre ...
. During the Pre-Illinoian Stage, the Laurentide Ice Sheet extended as far south as the
Missouri Missouri is a state in the Midwestern region of the United States. Ranking 21st in land area, it is bordered by eight states (tied for the most with Tennessee): Iowa to the north, Illinois, Kentucky and Tennessee to the east, Arkansas t ...
and
Ohio River The Ohio River is a long river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing southwesterly from western Pennsylvania to its mouth on the Mississippi River at the southern tip of ...
valleys. It was up to thick in
Nunavik Nunavik (; ; iu, ᓄᓇᕕᒃ) comprises the northern third of the province of Quebec, part of the Nord-du-Québec region and nearly coterminous with Kativik. Covering a land area of north of the 55th parallel, it is the homeland of the ...
,
Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirte ...
,
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...
, but much thinner at its edges, where
nunatak A nunatak (from Inuit language, Inuit ''nunataq'') is the summit or ridge of a mountain that protrudes from an ice field or glacier that otherwise covers most of the mountain or ridge. They are also called glacial islands. Examples are natural p ...
s were common in hilly areas. It created much of the surface geology of southern Canada and the northern United States, leaving behind glacially scoured valleys,
moraines A moraine is any accumulation of unconsolidated debris ( regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice she ...
,
eskers An esker, eskar, eschar, or os, sometimes called an ''asar'', ''osar'', or ''serpent kame'', is a long, winding ridge of stratified sand and gravel, examples of which occur in glaciated and formerly glaciated regions of Europe and North Amer ...
and
glacial till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...
. It also caused many changes to the shape, size, and drainage of the Great Lakes. As but one of many examples, near the end of the last ice age,
Lake Iroquois Lake Iroquois can refer to: * Lake Iroquois (South Dakota) * Lake Iroquois (Vermont) in Vermont in the United States * Lake Iroquois, Illinois in Iroquois County in Illinois in the United States *Glacial Lake Iroquois Glacial Lake Iroquois was a ...
extended well beyond the boundaries of present-day
Lake Ontario Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north, west, and southwest by the Canadian province of Ontario, and on the south and east by the U.S. state of New York. The Canada–United States border sp ...
, and drained down the Hudson River into the Atlantic Ocean. Its cycles of growth and melting were a decisive influence on global
climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologi ...
during its existence. This is because it served to divert the
jet stream Jet streams are fast flowing, narrow, meandering air currents in the atmospheres of some planets, including Earth. On Earth, the main jet streams are located near the altitude of the tropopause and are westerly winds (flowing west to east) ...
southward, which would otherwise flow from the relatively warm
Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the conti ...
through
Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...
and
Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over t ...
. That gave the
Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, N ...
, otherwise a desert, abundant rainfall during ice ages, in extreme contrast to most other parts of the world which became exceedingly dry, though the effect of ice sheets in
Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
had an analogous effect on the rainfall in
Afghanistan Afghanistan, officially the Islamic Emirate of Afghanistan,; prs, امارت اسلامی افغانستان is a landlocked country located at the crossroads of Central Asia and South Asia. Referred to as the Heart of Asia, it is borde ...
, parts of
Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
, possibly western
Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
in winter, as well as
North Africa North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...
. Its melting also caused major disruptions to the global climate cycle, because the huge influx of low-
salinity Salinity () is the saltiness or amount of salt (chemistry), salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensio ...
water into the
Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...
via the Mackenzie River is believed to have disrupted the formation of
North Atlantic Deep Water North Atlantic Deep Water (NADW) is a deep water mass formed in the North Atlantic Ocean. Thermohaline circulation (properly described as meridional overturning circulation) of the world's oceans involves the flow of warm surface waters from the ...
, the very saline, cold, deep water that flows from the
Greenland Sea The Greenland Sea is a body of water that borders Greenland to the west, the Svalbard archipelago to the east, Fram Strait and the Arctic Ocean to the north, and the Norwegian Sea and Iceland to the south. The Greenland Sea is often defined a ...
. That interrupted the
thermohaline circulation Thermohaline circulation (THC) is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. The adjective ''thermohaline'' derives from '' thermo-'' referring to temp ...
, creating the brief
Younger Dryas The Younger Dryas (c. 12,900 to 11,700 years BP) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM, c. 27,000 to 20,000 years BP). The Younger Dryas was the last stag ...
cold epoch and a temporary re-advance of the ice sheet, which did not retreat from
Nunavik Nunavik (; ; iu, ᓄᓇᕕᒃ) comprises the northern third of the province of Quebec, part of the Nord-du-Québec region and nearly coterminous with Kativik. Covering a land area of north of the 55th parallel, it is the homeland of the ...
until 6,500 years ago. After the end of the Younger Dryas, the Laurentide Ice Sheet retreated rapidly to the north, becoming limited to only the Canadian Shield until even it became deglaciated. The ultimate collapse of the Laurentide Ice Sheet is also suspected to have influenced European agriculture indirectly through the rise of global sea levels. Canada's oldest ice is a 20,000-year-old remnant of the Laurentide Ice Sheet called the
Barnes Ice Cap The Barnes Ice Cap is an ice cap located in central Baffin Island, Nunavut, Canada. Geography It covers close to in the area of the Baffin Mountains. It has been thinning due to regional warming. Between 2004 and 2006, the ice cap was thinning ...
, on central
Baffin Island Baffin Island (formerly Baffin Land), in the Canadian territory of Nunavut, is the largest island in Canada and the fifth-largest island in the world. Its area is , slightly larger than Spain; its population was 13,039 as of the 2021 Canadia ...
.


Ice centers

During the
Late Pleistocene The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch withi ...
, the Laurentide ice sheet reached from the
Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico ...
eastward through the
Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
, into
New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...
, covering nearly all of
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...
east of the Rocky Mountains.Geologic Framework and Glaciation of the Central Area, 1-1-2006; Christopher L. Hill; Boise State University, Boise, Idaho; 2006. Three major ice centers formed in North America: the
Labrador , nickname = "The Big Land" , etymology = , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 ...
, Keewatin, and Cordilleran. The Cordilleran covered the region from the Pacific Ocean to the eastern front of the Rocky Mountains and the Labrador and Keewatin fields are referred to as the Laurentide Ice Sheet. Central North America has evidence of the numerous lobes and sublobes. The Keewatin covered the western interior plains of North America from the Mackenzie River to the Missouri River and the upper reaches of the
Mississippi River The Mississippi River is the List of longest rivers of the United States (by main stem), second-longest river and chief river of the second-largest Drainage system (geomorphology), drainage system in North America, second only to the Hudson B ...
. The Labrador covered spread over
eastern Canada Eastern Canada (also the Eastern provinces or the East) is generally considered to be the region of Canada south of the Hudson Bay/ Strait and east of Manitoba, consisting of the following provinces (from east to west): Newfoundland and Labra ...
and the northeastern part of the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
abutting the Keewatin lobe in the western
Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
and
Mississippi valley The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it ...
.


Cordilleran ice flow

The Cordilleran ice sheet covered up to at the
Last Glacial Maximum The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent. Ice sheets covered much of Northern North America, Northern Eu ...
. The eastern edge abutted the Laurentide ice sheet. The sheet was anchored in the
Coast Mountains The Coast Mountains (french: La chaîne Côtière) are a major mountain range in the Pacific Coast Ranges of western North America, extending from southwestern Yukon through the Alaska Panhandle and virtually all of the Coast of British Columbi ...
of
British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, for ...
and
Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest T ...
, south into the
Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...
of
Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...
. That is one and a half times the water held in the
Antarctic The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and othe ...
. Anchored in the mountain backbone of the west coast, the ice sheet dissipated north of the
Alaska Range The Alaska Range is a relatively narrow, 600-mile-long (950 km) mountain range in the southcentral region of the U.S. state of Alaska, from Lake Clark at its southwest endSources differ as to the exact delineation of the Alaska Range. ThBo ...
where the air was too dry to form glaciers. It is believed that the Cordilleran ice melted rapidly, in less than 4000 years. The water created numerous Proglacial lakes along the margins such as
Lake Missoula Lake Missoula was a prehistoric proglacial lake in western Montana that existed periodically at the end of the last ice age between 15,000 and 13,000 years ago. The lake measured about and contained about of water, half the volume of Lake Mic ...
, often leading to catastrophic floods as with the
Missoula Floods The Missoula floods (also known as the Spokane floods or the Bretz floods or Bretz's floods) were cataclysmic glacial lake outburst floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the las ...
. Much of the topography of
Eastern Washington Eastern Washington is the region of the U.S. state of Washington located east of the Cascade Range. It contains the city of Spokane (the second largest city in the state), the Tri-Cities, the Columbia River and the Grand Coulee Dam, the Hanf ...
and northern
Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...
and
North Dakota North Dakota () is a U.S. state in the Upper Midwest, named after the indigenous Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minnesota to the east, ...
was affected.


Keewatin ice flow

The Keewatin ice sheet has had four or five primary lobes identified ice divides extending from a dome over west-central Keewatin. Two of the lobes abut the adjacent Labrador and Baffin ice sheets. The primary lobes flow (1) towards
Manitoba Manitoba ( ) is a Provinces and territories of Canada, province of Canada at the Centre of Canada, longitudinal centre of the country. It is Canada's Population of Canada by province and territory, fifth-most populous province, with a population o ...
and
Saskatchewan Saskatchewan ( ; ) is a Provinces and territories of Canada, province in Western Canada, western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and on t ...
; (2) toward
Hudson Bay Hudson Bay ( crj, text=ᐐᓂᐯᒄ, translit=Wînipekw; crl, text=ᐐᓂᐹᒄ, translit=Wînipâkw; iu, text=ᑲᖏᖅᓱᐊᓗᒃ ᐃᓗᐊ, translit=Kangiqsualuk ilua or iu, text=ᑕᓯᐅᔭᕐᔪᐊᖅ, translit=Tasiujarjuaq; french: b ...
; (3) towards the
Gulf of Boothia The Gulf of Boothia is a body of water in Nunavut, Canada. Administratively it is divided between the Kitikmeot Region on the west and the Qikiqtaaluk Region on the east. It merges north into Prince Regent Inlet, the two forming a single bay w ...
, and (4) towards the
Beaufort Sea The Beaufort Sea (; french: Mer de Beaufort, Iñupiaq: ''Taġiuq'') is a marginal sea of the Arctic Ocean, located north of the Northwest Territories, the Yukon, and Alaska, and west of Canada's Arctic islands. The sea is named after Sir ...
.Late Wisconsinan and Holocene History of the Laurentide Ice Sheet, 10.7202/032681ar; Arthur S. Dyke, Victor K. Prest; Geological Survey of Canada; Ottawa, Ontario; 1987; http://id.erudit.org/iderudit/032681ar.


Labrador ice flow

The
Labrador ice sheet , nickname = "The Big Land" , etymology = , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 ...
flowed across all of
Maine Maine () is a state in the New England and Northeastern regions of the United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Canadian provinces of New Brunswick and Quebec to the northeast and nor ...
and into the Gulf of St. Lawrence, completely covering the
Maritime Provinces The Maritimes, also called the Maritime provinces, is a region of Eastern Canada consisting of three provinces: New Brunswick, Nova Scotia, and Prince Edward Island. The Maritimes had a population of 1,899,324 in 2021, which makes up 5.1% o ...
. The Appalachian Ice Complex, flowed from the
Gaspé Peninsula The Gaspé Peninsula, also known as Gaspesia (; ), is a peninsula along the south shore of the Saint Lawrence River that extends from the Matapedia Valley in Quebec, Canada, into the Gulf of Saint Lawrence. It is separated from New Brunswick ...
over
New Brunswick New Brunswick (french: Nouveau-Brunswick, , locally ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. It is the only province with both English and ...
, the Magdalen Shelf, and
Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native Eng ...
. The Labrador flow extended across the mouth of the St. Lawrence River, reaching the
Gaspé Peninsula The Gaspé Peninsula, also known as Gaspesia (; ), is a peninsula along the south shore of the Saint Lawrence River that extends from the Matapedia Valley in Quebec, Canada, into the Gulf of Saint Lawrence. It is separated from New Brunswick ...
and across
Chaleur Bay frame, Satellite image of Chaleur Bay (NASA). Chaleur Bay is the large bay in the centre of the image; the Gaspé Peninsula is to the north and the Gulf of St. Lawrence is seen to the east.">Gulf_of_St._Lawrence.html" ;"title="Gaspé Peninsula ...
. From the Escuminac center on the Magdalen Shelf, flowed onto the
Acadian Peninsula The Acadian Peninsula (french: Péninsule acadienne) is situated in the northeastern corner of New Brunswick, Canada, encompassing portions of Gloucester and Northumberland Counties. It derives its name from the large Acadian population located ...
of
New Brunswick New Brunswick (french: Nouveau-Brunswick, , locally ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. It is the only province with both English and ...
and southeastward, onto the Gaspe, burying the western end of
Prince Edward Island Prince Edward Island (PEI; ) is one of the thirteen provinces and territories of Canada. It is the smallest province in terms of land area and population, but the most densely populated. The island has several nicknames: "Garden of the Gulf", ...
and reached the head of
Bay of Fundy The Bay of Fundy (french: Baie de Fundy) is a bay between the Canadian provinces of New Brunswick and Nova Scotia, with a small portion touching the U.S. state of Maine. It is an arm of the Gulf of Maine. Its extremely high tidal range is t ...
. From the Gaspereau center, on the divide crossing New Brunswick flowed into the Bay of Fundy and Chaleur Bay. In New York, the ice that covered Manhattan was about 2,000 feet high before it began to melt in about 16,000 BC. The ice in the area disappeared around 10,000 BC. The ground in the New York area has since risen by more than 150 ft because of the removal of the enormous weight of the melted ice.


Baffin ice flow

The Baffin ice sheet was circular and centered over the
Foxe Basin Foxe Basin is a shallow oceanic basin north of Hudson Bay, in Nunavut, Canada, located between Baffin Island and the Melville Peninsula. For most of the year, it is blocked by sea ice (fast ice) and drift ice made up of multiple ice floes. ...
. A major divide across the basin, created a westward flow across the
Melville Peninsula Melville Peninsula is a large peninsula in the Canadian Arctic north of Hudson Bay. To the east is Foxe Basin and to the west the Gulf of Boothia. To the north the Fury and Hecla Strait separates it from Baffin Island. To the south Repulse B ...
, from an eastward flow over
Baffin Island Baffin Island (formerly Baffin Land), in the Canadian territory of Nunavut, is the largest island in Canada and the fifth-largest island in the world. Its area is , slightly larger than Spain; its population was 13,039 as of the 2021 Canadia ...
and
Southampton Island Southampton Island (Inuktitut: ''Shugliaq'') is a large island at the entrance to Hudson Bay at Foxe Basin. One of the larger members of the Arctic Archipelago, Southampton Island is part of the Kivalliq Region in Nunavut, Canada. The area of th ...
. Across southern Baffin Island, two divides created four additional lobes. The Penny Ice Divide split the
Cumberland Peninsula Cumberland Peninsula is a peninsula in the southeastern part of Baffin Island in Nunavut, Canada. It is located between 64°56' and 67°57' north latitude, and 61°56' to 68° west longitude. The Arctic Circle crosses the peninsula, with the Labr ...
, where
Pangnirtung Pangnirtung (or Pang, also Pangniqtuuq, in syllabics: ᐸᖕᓂᖅᑑᖅ ) is an Inuit hamlet, in the Qikiqtaaluk Region of the Canadian territory of Nunavut, located on Baffin Island. Pangnirtung is situated on a coastal plain at the coast of P ...
created flow toward Home Bay on the north and Cumberland Sound on the south. The Amadjuak Ice Divide on the Hall Peninsula, where
Iqaluit Iqaluit ( ; , ; ) is the capital of the Provinces and territories of Canada, Canadian territory of Nunavut, its largest community, and its only city. It was known as Frobisher Bay from 1942 to 1987, after the Frobisher Bay, large bay on the c ...
sits created a north flow into
Cumberland Sound Cumberland Sound (french: Baie Cumberland; Inuit: ''Kangiqtualuk'') is an Arctic waterway in Qikiqtaaluk Region, Nunavut, Canada. It is a western arm of the Labrador Sea located between Baffin Island's Hall Peninsula and the Cumberland Peninsula ...
and a south flow into the
Hudson Strait Hudson Strait (french: Détroit d'Hudson) links the Atlantic Ocean and Labrador Sea to Hudson Bay in Canada. This strait lies between Baffin Island and Nunavik, with its eastern entrance marked by Cape Chidley in Newfoundland and Labrador and ...
. A secondary Hall Ice Divide formed a link to a local ice cap on the Hall Peninsula. The current ice caps on Baffin Island are thought to be a remnant from this time period, but it was not a part of the Baffin ice flow, but an autonomous flow.


See also

*
Canadian Shield The Canadian Shield (french: Bouclier canadien ), also called the Laurentian Plateau, is a geologic shield, a large area of exposed Precambrian igneous and high-grade metamorphic rocks. It forms the North American Craton (or Laurentia), the anc ...
*
Glacial history of Minnesota The glacial history of Minnesota is most defined since the onset of the last glacial period, which ended some 10,000 years ago. Within the last million years, most of the Midwestern United States and much of Canada were covered at one time or ...
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Driftless Area The Driftless Area, a topographical and cultural region in the American Midwest, comprises southwestern Wisconsin, southeastern Minnesota, northeastern Iowa, and the extreme northwestern corner of Illinois. Never covered by ice during the las ...
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Lake Agassiz Lake Agassiz was a large glacial lake in central North America. Fed by glacial meltwater at the end of the last glacial period, its area was larger than all of the modern Great Lakes combined. First postulated in 1823 by William H. Keating, i ...
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Wisconsin glaciation The Wisconsin Glacial Episode, also called the Wisconsin glaciation, was the most recent glacial period of the North American ice sheet complex. This advance included the Cordilleran Ice Sheet, which nucleated in the northern North American Cord ...
*Laurentide Ice Sheet ** Cordilleran ice sheet ** Keewatin ice sheet **
Labrador ice sheet , nickname = "The Big Land" , etymology = , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 ...
** Baffin ice sheet


References


Further reading

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External links


The Retreat of Glaciers in North America
(MPEG-Video) {{DEFAULTSORT:Laurentide Ice Sheet Ice sheets Glaciology Glaciology of Canada Glaciology of the United States Geology of New York (state) Geology of Illinois Geology of Kansas Geology of Missouri Ice ages Pleistocene Geological history of the Great Lakes Midwestern United States Northeastern United States